Why do some elements have symbols that are very different from the english names of elements

Why doesn't heat added to water make the tempature rise above 100c

One of the few xenon compounds that form is cesium xenon heptafluoride (csxef7). how many moles of csxef7 can be produced from the reaction of 13.0 mol cesium fluoride with 12.5 mol xenon hexafluoride? csf(s) + xef6(s) csxef7(s)

Silver reacts with oxygen to produce silver oxide. (write balanced chemical equation and identify type of chemical reaction.)